METHOD AND SYSTEM FOR VOLTAGE REGULATION, CONTROL, PROTECTION AND MONITORING OF STATE OF ON-LOAD TAP CHANGERS OF POWER TRANSFORMERS, VOLTAGE REGULATORS, AND CAPACITOR BANKS
First Claim
1. A METHOD FOR VOLTAGE REGULATION, CONTROL, PROTECTION AND MONITORING OF STATE OF ON-LOAD TAP CHANGERS OF POWER TRANSFORMERS, VOLTAGE REGULATORS, AND CAPACITOR BANKS comprising:
- using a voltage regulation system (S) that has six or more sets (20A, 20B, 20C) of voltage regulation parameters (21) available for programming by a user, each of these sets (20A, 20B, 20C) being adjustable in an independent manner for a given prevailing load (L) condition, each set being the parameters (21), and wherein the parameters comprise;
a desired rated voltage at a load;
a voltage variance percentage allowed over and below rated voltage;
time delay adjustments for CDC (15) actuation in order to correct voltage;
choice of linear or reverse time delay type; and
parameters referring to voltage drop in the line.
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Abstract
A method for voltage regulation, control, protection and monitoring of state of on-load tap changers of power transformers, voltage regulators, and capacitor banks comprising: uses a voltage regulation system that has sets of voltage regulation parameters available for programming by a user. Each of these sets is adjustable in an independent manner for a given prevailing load condition. The parameters include a desired rated voltage at a load; a voltage variance percentage allowed over and below rated voltage; time delay adjustments for CDC (15) actuation in order to correct voltage; choice of linear or reverse time delay type; and parameters referring to voltage drop in the line.
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Citations
10 Claims
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1. A METHOD FOR VOLTAGE REGULATION, CONTROL, PROTECTION AND MONITORING OF STATE OF ON-LOAD TAP CHANGERS OF POWER TRANSFORMERS, VOLTAGE REGULATORS, AND CAPACITOR BANKS comprising:
- using a voltage regulation system (S) that has six or more sets (20A, 20B, 20C) of voltage regulation parameters (21) available for programming by a user, each of these sets (20A, 20B, 20C) being adjustable in an independent manner for a given prevailing load (L) condition, each set being the parameters (21), and wherein the parameters comprise;
a desired rated voltage at a load; a voltage variance percentage allowed over and below rated voltage; time delay adjustments for CDC (15) actuation in order to correct voltage; choice of linear or reverse time delay type; and parameters referring to voltage drop in the line. - View Dependent Claims (2, 3, 4, 5)
- using a voltage regulation system (S) that has six or more sets (20A, 20B, 20C) of voltage regulation parameters (21) available for programming by a user, each of these sets (20A, 20B, 20C) being adjustable in an independent manner for a given prevailing load (L) condition, each set being the parameters (21), and wherein the parameters comprise;
- 6. A method for voltage regulation, control, protection and monitoring of state of on-load tap changers of power transformers, voltage regulators, and capacitor banks wherein a voltage regulation system (S) has two independent time delay parameters (31L, 31R) available for programming by a user, wherein one of the delay parameters (31R) is used when a measured load voltage (13) is below a preprogrammed rated voltage, and the other delay parameter (31L) is used when the measured load voltage (13) is above the preprogrammed rated voltage.
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8. A method for voltage regulation, control, protection and monitoring of state of on-load tap changers of power transformers, voltage regulators, and capacitor banks, wherein a voltage regulation system (S) performs recording of measurements in non-volatile memory (9) according to parameters programmed by a user comprising:
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a time interval for periodic recording; selecting variables (9A) to be recorded in a memory (9), including;
a measured voltage (17), a load voltage (13), a load current (17′
) and an OLTC tap position (12), and calculated variables including;
active and reactive power, frequency and load power factor;a recording mode (9B) for each of the variables (9A) selected for recording, the recording mode (9B) selected from a group including;
instantaneous value of the variable, average value of the variable calculated during the interval since last recording, root mean square of the variable calculated during the interval since last recording, maximum value of the variable observed during an interval since last recording or minimum value of the variable observed during the interval since last recording; andselecting more than one recording mode (9B) for each of the variables (9A) selected for recording.
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9. A method for voltage regulation, control, protection and monitoring of state of on-load tap changers of power transformers, voltage regulators, and capacitor banks, wherein a voltage regulation system (S) performs the OLTC Maintenance Assistant function by measuring an OLTC tap position measurement through a tap measuring input (12) comprising:
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counting a total number of OLTC (15) operations since a beginning of OLTC operation, the count being increased every time the OLTC tap position measurement input (12) changes; counting a partial number of OLTC (15) operations since a last maintenance performed on the OLTC, the counter being increased every time the OLTC tap position measurement input (12) changes; wherein both a total counting and a partial counting are increased by one unit every time the OLTC tap position measurement input (12) changes, except for tap positions previously selected and programmed by a user with an specific number to be used to increase both counters; wherein both the total counting and the partial counting are recorded in a voltage regulation system (S) non-volatile memory (9); wherein both the total counting and the partial counting can have values programmed by the user, so as to allow an application of the OLTC Maintenance Assistant function with old OLTCs; wherein based on a user programming of a number of operations after which OLTC maintenance must be performed, the voltage regulation system (S) issues a warning indicating a need for OLTC maintenance when a partial operation counting is equal or higher than the number of operations after which OLTC maintenance must be performed; wherein the voltage regulation system (S) calculates an average number of OLTC operations per day by dividing a number of operation in the last X days by X elapsed days, X being a time interval programmable by the user; wherein the voltage regulation system (S) calculates a remaining time for reaching the number of operations for OLTC maintenance, according to a formula;
Y=((No. of operations for maintenance)+(partial operation counter))/(Average daily operations);wherein the voltage regulation system (S) issues a maintenance warning indicating that OLTC maintenance will be necessary within Y days, when a value calculated for Y is equal or lower than a number of days for advanced maintenance warning programmed by the user; and wherein the maintenance warnings will remain active in the voltage regulation system (S) until the user performs a manual warning reset at a keyboard (3), informing the voltage regulation system (S) that maintenance has been performed;
once the manual reset is made, partial operation counting since the last maintenance is zeroed and warnings for maintenance are switched off. - View Dependent Claims (10)
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Specification